Search Publications
The nature of the faint galaxies in the Hubble Deep Field
Georgakakis, A.; Rowan-Robinson, M.; Mobasher, B. +1 more
We present a study of the galaxies found in the Hubble Deep Field (HDF). A high proportion of HDF galaxies are undergoing a strong episode of star formation, as evidenced by their very blue colours. A wide range of morphological types is found, with a high proportion of peculiar and merger morphologies. Fitting the multiband spectra with redshifte…
Faint galaxy counts as a function of morphological type in a hierarchical merger model
Cole, S.; Baugh, C. M.; Frenk, C. S.
The unprecedented resolution of the refurbished Wide Field and Planetary Camera 2 (WFPC2) on the Hubble Space Telescope (HST) has led to major advances in our understanding of galaxy formation. The high image quality in the Medium Deep Survey and Hubble Deep Field has made it possible, for the first time, to classify faint distant galaxies accordi…
Dust formation in the Cassiopeia A supernova.
Boulanger, F.; Fransson, C.; Ballet, J. +5 more
High angular resolution (6") spectro-imaging observations of Cassiopeia A, the youngest supernova remnant of our galaxy, were performed with ISOCAM, the mid-infrared camera on board of the Infrared Space Observatory (ISO). The remnant was fully mapped with the LW8 filter (10.7-12µm), which probes mainly dust thermal emission. Emission is see…
Hubble Space Telescope Ultraviolet Spectrum of ARP 102B, the Prototypical Double-peaked Emission-Line AGN
Filippenko, Alexei V.; Eracleous, Michael; Halpern, Jules P. +1 more
UV spectra of the nucleus of the elliptical galaxy Arp 102B were obtained with the HST's Faint Object Spectrograph in order to investigate the UV emission-line counterparts of its unusual double-peaked Balmer lines. Broad Mg II λ2798 is present with nearly the same profile as the Balmer lines (peaks separated by ~12,000 km s^-1^), and a typical Mg…
Wavelength and direction filtering by magnetic measurements at satellite arrays: Generalized minimum variance analysis
Glassmeier, K. H.; Motschmann, U.; Southwood, D. J. +2 more
The main goal of the Cluster mission, consisting of four identical spacecraft, is the spatial resolution of plasma structures. For the determination of the wave vectors of a wave field from four positions, classical Fourier analysis is inappropriate. We develop a generalized minimum variance technique which gives a high wave vector resolution thou…
EUVE Observations of U Geminorum in Outburst
Szkody, Paula; Raymond, John C.; Long, Knox S. +2 more
We have observed U Gem during the peak and declining phases of a wide outburst in 1993 December with the Extreme Ultraviolet Explorer (EUVE) satellite. At peak, U Gem was one of the brightest EUV sources in the sky. The spectrum of the source is complex. Fitted to a blackbody spectrum, the apparent temperature at peak is ∼140,000 K, the luminosity…
ISO-SWS spectroscopy of ARP 220: a highly obscured starburst galaxy.
Lutz, D.; Genzel, R.; Sturm, E. +8 more
We report the first 2.4-45µm spectroscopic study of Arp 220 obtained with the Short Wavelength Spectrometer onboard ISO. Observations of mid infrared lines penetrate deep into the highly obscured regions where the luminosity originates and give direct clues to their sources of excitation. From the observed Brackett line ratios and from the […
Double-Peaked Broad Emission Lines in the Nucleus of M81
Heckman, Timothy M.; Bower, Gary A.; Wilson, Andrew S. +1 more
We present recent optical spectroscopy of the nucleus of the spiral galaxy M81 obtained with the post-COSTAR Faint Object Spectrograph (FOS) aboard Hubble Space Telescope (HST). The spectra reveal a new double- peaked broad component in the profiles of Hα and Hβ, the FWZI of which are ~14000 and 11000 km s^-1^, respectively. Such double-peaked bro…
Volumetric heating in coronal streamers
Wu, S. T.; Suess, S. T.; Wang, A. -H.
The addition of a volumetric heat source to a coronal streamer model produces distinct, important changes in the model. Originally, such heating was added to meet the observational requirement for a thin current sheet above streamers. Here we report additional consequences of a volumetric heat source, together with the effects of redistribution of…
The compact radio nucleus of the Seyfert galaxy NGC 1068
Muxlow, T. W. B.; Antonucci, R. R. J.; Holloway, A. J. +2 more
We present a 5-GHz MERLIN map of the central arcsecond of the Seyfert 2 galaxy NGC 1068. We detect the four-component structure reported in earlier observations. The higher angular resolution and sensitivity of the MERLIN measurements show extended emission consistent with a flaring jet which appears to originate from the vicinity of a 100-mas com…